Water wash for stabilized silver halide photographic materials

ABSTRACT

AN IMPROVED PROCESS FOR STABILIZING A DEVELOPED SILVER HALIDE LIGHT-SENSITIVE MATERIAL UTILIZING A THIOCYANATE OR THIOUREA WHICH FURTHER COMPRISES SUBJECTING THE LIGHTSENSITIVE MATERIAL TO A WASHING BATH TREATMENT WHEREIN THE WASHING FLUID COMPRISES WATER AS THE SOLE COMPONENT WHICH IS UTILIZED TO REMOVE STABILIZING AGENTS, THE WASHING BATH BEING CONDUCTED FOR A PERIOD OF TIME SHORTER THAN SIXTY SECONDS AFTER EXPOSING, DEVELOPING AND STABILIZING SAID LIGHT-SENSITIVE MATERIAL.

Jpn. 26,1971

PHOTOGRAPMC MNSITY SHUHNICHIRO TSUCHIDA ETAL 3,558,313

WATER WASH FOR STABILIZED SILVER HALIDE PHOTOGRAPHIC MATERIALSPHOTOGRAPMC DENSITY Filed Feb. 24, 1966 FIG] WASHING PERM!) III SECONDSHDTDGRIPHIC DENSITY SNUNICMRO TSUCIIM TOIMKI IIYITA IKZHMIKO TAKAMSII 37J M, M,

-M) v A'I'IORNEY:

MING PERU) IN 8COIl0$ INVENTORS United States Patent Ofice 3,558,313WATER WASH FOR STABILIZED SILVER HALIDE PHOTOGRAPHIC MATERIALSShunichiro Tsuchida, Tomiaki Miyata, and Michihiko Takahashi, Kanagawa,Japan, assignors to Fuji Shashin Film Kabushiki Kaisha, Kanagawa, JapanFiled Feb. 24, 1966, Ser. No. 529,696 Claims priority, applicationJapan, Feb. 24, 1965, 40/ 10,328 Int. Cl. G03c 5/26, 5/38 US. CI. 96-503 Claims ABSTRACT OF THE DISCLOSURE An improved process for stabilizinga developed silver halide light-sensitive material utilizing athiocyanate or thiourea which further comprises subjecting thelightsensitive material to a washing bath treatment wherein the washingfluid comprises water as the sole component which is utilized to removestabilizing agents, the washing bath being conducted for a period oftime shorter than sixty seconds after exposing, developing andstabilizing said light-sensitive material.

The present invention relates to a process for further increasing thestability of photographic images of silver halide photographic materialswhich have been developed and subjected to a so-called stabilizingtreatment.

In order to make light-insensitive the unexposed silver halide of asilver halide photographic material, after light exposure anddevelopment, there have hitherto been adopted the following two methods.That is, the developed silver halide photographic material is fixed andthe remaining silver halide is converted into a light-unstable silvercomplex salt, Which is then removed from the photographic material bywater-washing. Or, the photographic material is subjected to astabilizing treatment requiring no water-washing treatment to convertthe unexposed silver halide into a light-stable silver complex salt,which is left in the thus stabilized silver halide photographic emulsionwithout being removed by water-washing. According to the latterstabilizing treatment, the treatment can be done quickly, but, ingeneral, the qualities of the image are accompanied with many faults.

After exposure and development, there remains silver halide at theunexposed areas of the silver halide photographic material and metallicsilver is formed at the exposed areas of the photographic material. Inthe subsequent stabilizing treatment, a silver complex salt-formingagent is supplied not only to the unexposed area, that is, the silverhalide-remaining areas, but also to the exposed areas, that is, themetallic silver-formed areas. Hence the stabilized silver halidephotographic material is dried and preserved in the state in which itcontains the silver complex salt-forming agent together with the silvercomplex salt, since water-washing treatment is not applied. I

However, since the silver complex salt-forming agent is used inconsiderable excess of a theoretical amount to assure the stability ofimages to light, the hygroscopic property of the agent impedes thedrying procedure and makes sticky the surface of the stabilizedphotographic material to be preserved. Further, there is a tendency inthis case for the metallic silver composing the image to be graduallyoxidized by the silver complex salt-forming agent into a silver complexsalt, which reduces the photographic density of the image. That is, whenthe thus stabilized silver halide photographic material is preserved inthe air, the color of the image of the photographic material isconverted from black to brown or yellow owing to the reduction inphotographic density and in an excessive case, the image tends todisappear. Such a phenom- 3,558,313 Patented Jan. 26, 1971 enon isliable to occur when the stabilized silver halide photographic materialis preserved at high temperature and at high humidity.

For overcoming these difiiculties, the adoption of water-washing may beconsidered. But water-washing has been considered to be undesirable inthe case of applying stabilizing treatment, because (1) the silvercomplex salt formed by the conventional stabilizing treatment is stablein the state that the silver complex salt-forming is present in anexcessive amount, and (2) because, even though the silver complex saltand the silver complex salt-forming agent are washed out by water, aslight amount of silver complex salt remains in the photographicmaterial, in the case of using as a stabilizing agent thiocyanates orthiourea, which is very unstable and reduces markedly the image.

However, the inventors have found that the application of washing to thethus stabilized silver halide photographic material for a limited periodof time is desirable.

According to the process of this invention, a stabilized silver halidephotographic material is subjected to washing with water or an aqueoussolution for a period of time to secure the stability of the silvercomplex salt, that is, for a period shorter than 60 seconds, whereby thereduction of the photographic density of the image, the discoloration ofthe photographic, and the formation of sticky surface of thephotographic material are prevented. Moreover, in the invention, theapplication of ferrotype drying to the stabilized silver halidephotographic material is possible.

The washing bath in this invention may be used until the concentrationof the silver complex salt-forming agent in the bath reaches 3%.

In the washing bath in this invention may be added effectively afluorescent bleaching agent, such as Whitex BH (made by Sumitomo KagakuK.K.) and Kayaphor S (Nihou Kayaku K.K.) to increase the whiteness.

Further, into the washing bath in this invention may be added anultraviolet absorbing agent, such as, HPT (made by Dupont Company) andUV400 (made by Gen- 1eral Aniline & Film Corp.) to increase thestability of ight.

Furthermore, into the washing bath of this invention may be added aphoto-wetting agent, such as, Dry Well (made by Fuji Photo-Film Co.),Konidux (made by Konishi Roku-Shashin Kogyo K.K.), and other surfaceactive agents.

Still further, into the washing bath in this invention may be added ahardening agent to reduce the stickiness of the surface of the emulsionlayer of the photographic material, such as, potassium alum, chromiumalum, acetic acid, formaline, etc.

The following are the examples of this invention.

EXAMPLE 1 A silver halide photographic light-sensitive paper and asilver halide photographic light-sensitive film were exposed, developedtreated in a stabilizing solution mainly comprising ammoniumthiocyanate, and then subjected to water-washing. The results of theprocedures are shown in FIG. 1 of the accompanying drawings, in whichthe graph shows the relation of the photographic density and the washingperiod. The solid line corresponds to the case of the silver halidephotographic paper and the dotted line to the case of the silver halidephotographic film. In the positive side (+AD) of the photographicdensity in the graph there is shown the increased photographic densityof the unexposed areas of the photographic materials sub- {acted to aforced deterioration test of 15 hours by means of Shimazu Xenon Testerand in the negative side (AD) in the graph is shown the reducedphotographic density of the areas of the photographic material havingthe photographic density of 1.8 (D) subjected to the forceddeterioration test for days at the temperature of 50 C. and humidity of90%.

The results show that the water-washing treatment for a period ofshorter than 60 seconds is effective for the prevention of reduction ofphotographic density of the photographic image by heat and humiditywhile sufficiently securing the light-stability of the image.

EXAMPLE 2 Instead of water-bath washing in Example 1, waterspray washingwas conducted and the results are shown in FIG. 2 of the accompanyingdrawing in which the testing procedures are the same as those in thecase of FIG. 1 in Example 1, As shown in the graph of FIG. 2, waterspraywashing of shorter than 5 seconds is effective for preventing thereduction of photographic density of the photographic images by heat andhumidity while securing the stability of the photographic material tolight.

EXAMPLE 3 A silver halide photographic light-sensitive paper and asilver halide photographic light-sensitive film were exposed, developed,treated in a stabilizing solution mainly comprising thiourea, and thensubjected to water-washing. The results are shown in FIG. 3 of theaccompanying drawing. The testing procedures are the same as in the caseof Example 1.

It is clear from the results, that, when the water-washing period isshorter than 5 seconds, the application thereof is sufficientlyeffective for the prevention of the reduction of photographic density ofimages by moisture and heat while securing its stability to light as inExample 1.

EXAMPLE 4 Into 1 liter of water-washing bath was dissolved 5 g. of afluorescent bleaching agent, Whitex BH. When a stabilized silver halidephotographic light-sensitive paper was treated by the bath as in Example1, the whiteness of the white ground of the photographic paper wasincreased and the reduction of photographic density of the image wassufficiently prevented. The results of testing preservability of thestabilized silver halide photographic paper subjected to the washingtreatment for 2 seconds and a stabilized silver halide photographicpaper subjected to no washing treatment (comparative sample) by thedeterioration test, in the same manner as in Example 1, are as follows:

AD +AD Non-washed image 0. 60 0. 01 Washed image 0. 25 0. 01

EXAMPLE 5 -AD +AD Non-washed image 0. 60 0. 01 Washed image 0. 20 O. 01

EXAMPLE 6 A washing bath prepared by dissolving ml. of an ultravioletabsorber HPT in 1 liter of water-washing bath was used. Decoloring ofthe image was prevented and also the reduction of photographic densityof the 4 image was sufficiently prevented. The results of the tests ofthe preservability of the stabilized silver halide photographic papersubjected to the washing treatment for 2 seconds and a stabilizedcomparative silver halide photographic paper subjected to no washingtreatment are as follows:

AD +Al) Non-washed image 0. 58 0. 02 Washed image 0. 18 0.00

EXAMPLE 7 AD +AD Non-washed image 0. 0. 01 Washed image 0. 11 0. 00

EXAMPLE 8 A washing bath prepared by dissolving 15 g. of potassium alumand 10 ml. of acetic acid as a hardening agent in 1 liter ofwater-washing bath was used. By the treatment, the surface of theemulsion layer of a stabilized silver halide photographic material washardened to reduce the stickiness of the surface and the reduction ofthe photographic density of the image was sutficiently prevented. Theresults of the tests of the preservability of the stabilized silverhalide photographic paper and silver halide photographic film subjectedto the washing treatment for 30 seconds and comparative samplessubjected to no washing treatment are as follows:

AD +AD Paper Film Paper Film Non-washed image O. 57 1. 00 0. 01 0. 01Washed image 0. 14 0. 18 O. 02 0. O1

EXAMPLE 9 A washing bath prepared by dissolving 15 ml. of Formalin(37%), 0.5 g. of boric acid, and 5.5 g. of sodium carbonate as ahardening agent into 1 liter of a waterwashing bath was used. By thetreatment, the surface of the emulsion layer of a silver halidephotographic material was hardened to reduce the stickiness and also thereduction of the photographic density of the image was sufficientlyprevented. The results of the preservability tests are as follows:

AD +AD Paper Film Paper Film Non-washed image 0. 58 1. 00 0. 01 0. 01Washed image O. 07 0. 05 0. 02 0. 00

EXAMPLE 10 together with the results from tests on comparativestabilized photographic materials subjected to no washing treatment bythe deterioration test, as in Example 1:

-AD +AD Paper Film Paper Film Non-washed image 0.60 0.95 0.01 0.00Washed image 0.22 0.14 03 0.00

EXAMPLE 11 -AD +AD Paper Film Paper Film Non-washed image 0. 60 0. 980.01 0. 00 Washed image 0. 25 0. 17 0. 03 0. 00

What we claim is:

1. In the process for stabilizing a developed silver halidelight-sensitive material utilizing a member selected from the groupconsisting of thiocyanates and thiourea wherein the silver halidelight-sensitive material is exposed, developed, stabilized, and dried,the improvement which comprises subjecting the light-sensitive materialto a washing bath treatment for a period of time shorter than seconds,said washing bath consisting solely of water, said treatment being theonly intervening step between said stabilizing and said drying step.

2. The process as claimed in claim 1 wherein said light-sensitivematerial is a silver halide light-sensitive film.

3. The process as claimed in claim 1 wherein said lightsensitivematerial is a silver halide light-sensitive paper.

References Cited UNITED STATES PATENTS 2,367,516 1/1945 Muehler et al96-50 3,212,895 10/1965 Barber et al. 9661 3,250,617 5/1966 Sawdey 96-503,356,502 12/1967 Nasu et al. 96-50 FOREIGN PATENTS 1,233,010 4/ 1959France 9661 39/25,774 Japan 96--61 OTHER REFERENCES Clafkides, P.Photographic Chemistry,, vol. I, 1958, pp. 158-60.

Focal Encyclopedia, vol. II, 1958, p. 1103.

NORMAN G. TORCHIN, Primary Examiner M. F. KELLEY, Assistant Examiner US.Cl. X.R. 96-61

